{- |

Module : $Header$

Description : Signature for common logic

Copyright : (c) Karl Luc, DFKI Bremen 2010

License : GPLv2 or higher, see LICENSE.txt

Maintainer : kluc@informatik.uni-bremen.de

Stability : experimental

Portability : portable

Definition of signatures for common logic

-}

module CommonLogic.Sign

(Sign (..)

, pretty -- pretty printing

, emptySig -- empty signature

, isSubSigOf -- sub signature of signature

, sigDiff -- Difference of Signatures

, unite -- union of signatures

, uniteL -- union of a list ofsignatures

, sigUnion -- Union for Logic.Logic

, isSeqMark -- is sequence marker?

, isStringSeqMark

, sigUnionL -- union of a list ofsignatures

) where

import qualified Data.Set as Set

import Common.Id

import Common.Result

import Common.Doc

import Common.DocUtils

-- | Datatype for common logic Signatures

data Sign = Sign { items :: Set.Set Id

, discourseItems :: Set.Set Id

} deriving (Eq, Ord, Show)

-- TODO function testing whether an ID is a sequence marker

instance Pretty Sign where

pretty = printSign

-- | The empty signature

emptySig :: Sign

emptySig = Sign { items = Set.empty

, discourseItems = Set.empty

}

-- | pretty printing for Signatures

printSign :: Sign -> Doc

printSign s =

hsep [text "%{vocabulary"

, sepByCommas $ map pretty $ Set.toList $ items s

, text "}%"]

-- | Determines if sig1 is subsignature of sig2

isSubSigOf :: Sign -> Sign -> Bool

isSubSigOf sig1 sig2 = Set.isSubsetOf (items sig1) $ items sig2

-- | difference of Signatures

sigDiff :: Sign -> Sign -> Sign

sigDiff sig1 sig2 = Sign {

items = Set.difference (items sig1) $ items sig2,

discourseItems = Set.difference (discourseItems sig1) $ items sig2

}

-- | Unite Signatures

sigUnion :: Sign -> Sign -> Result Sign

sigUnion s1 = Result [Diag Debug "All fine sigUnion" nullRange]

. Just . unite s1

-- | Unite Signature in a list

sigUnionL :: [Sign] -> Result Sign

sigUnionL (sig : sigL) = sigUnion sig (uniteL sigL)

sigUnionL [] = return emptySig

unite :: Sign -> Sign -> Sign

unite sig1 sig2 = Sign {

items = Set.union (items sig1) $ items sig2,

discourseItems = Set.union (discourseItems sig1) $ discourseItems sig2

}

-- TODO

isSeqMark :: Id -> Bool

isSeqMark _ = True

isStringSeqMark :: String -> Bool

isStringSeqMark s = take 3 s == "..."

uniteL :: [Sign] -> Sign

uniteL = foldr unite emptySig